This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The Bovine Viral Diarrhea Virus, similarly to HCV, is a member of Flaviviridae, and within this category, it is a Pestivirus. Matt Paulson has identified a mutation site of the HCV NS4B homologue in BVDV which resulted in an increased resistance following the infection (the cells did not die after infection). We aim to first identify the cellular interacting partners of the normal and the mutant protein. We have compared several isolation methods and using magnetic beads so far we have identified one of the expected interacting partners.